Technical Textile Division

1) COATING TEXTILE


1) COATING 

         Definition :-This Chemical  layer is applied in liquid form in a solvent or water base,  applied to one or both surfaces. Dependant upon the application method the liquid may require thick  so it does not soak through the fabric, or an anti-foaming agent to aid processing or cracking on chemical coated ect..,The thickness of the coating, or amount of product dependent of quality level , Bonding occurs through the drying process (evaporation) or through a curing process, required to for the end use like .,,ect..

                coating of micro or nano particles that adhere to the fibre surface forming a ‘substantial’, are below with image 

NOTE:From our mind-set we can produce  any type of  product through coating .

APPLICATION AREA COATED FABRIC 

 *)UV absorbers

                                                               *)Container caps for open container 

                                                               *)Inflatable boats

                                                               *)Roofing material in the Munich Airport Center 

                                                               *)Conveyor belts 

                                                               *) Blackout fabric for window curtain

                                                               *)Inkjet print Canvas fabric and 

                                                               *)Artist canvas

TYPES OR METHODS OR BRANCH OF Coating

a)Knife Coating (floating knife) or Direct Coating
b)Direct Roll Coating
c)Pad-Dry-Cure
d)Calender coating
e)Hot melt extrusion coating and 
f)spray coating etc...


a)Knife Coating (floating knife) or Direct Coating

AIM 
      To coat directly only one side of fabric , from the same fabric primary ,secondary, tertiary ect..,

  as per the GSM required for customer , which as to be supported for the base fabric   

Equipment 
                      Knife, Roller Smaller ,Roller Big , Base Fabric ready for coating ,Dryer machine , ect.. refer the production plant in India , Germany ,etc..   

working 

          In Knife Coating,the liquid coating is applied to the fabric while being run at tension under a floating knife blade, the distance between the fabric and the knife blade determines the thickness of the coating. The blade can be angled at any point For this process to be effective the liquid coating must be quite viscous in order to prevent it soaking through the fabric, the coating is then dried or cured by passing to dryer machine  

This technique is best used for fiber and Filament  yarns ,fabric For this type of coating to be most successful in industry , mostly duck design of fabric used fro coating and also plain 

Direct Roll Coating

In this process coating liquid is rolled onto the fabric by a roller suspended in the coating solution, often a blade is positioned close to the roller to ensure not too much coating solution is applied. 

Pad-Dry-Cure

Also referred to as Padding?, this technique, widely regarded as a textile finishing technique, can in fact be used to add a variety of coatings, but this usually refers to a fibre coating for the application of micro or nano materials or chemical compositions.

As shown in figure 5, the fabric is submerged in the coating solution then the excess squeezed out in the rollers, which dictates the pick-up percentage, the fabric is then dried and cured. 

Calender coating

Calender finishing involves the fabric passing through a set of heated rollers to singe off any surface fibres and add lustre and smoothness. Calender coating is the same principle in which the fabric passes through heated rollers, but through this process a coating is applied as demonstrated in figure 6. This image demonstrates the simultaneous coating of both sides of the fabric with the thickness of the coating determined by the width of the nip in-between the rollers, more rollers used can provide a thinner coating. 

Hot melt extrusion coating

Hot melt extrusion coating is applied in the same process as calendering with the coating being melted from granules fed to heated rollers which then nip the coating to the fabric. It is used to produce un-supported films and these freshly produced films are added direct to fabric. Its uses are mainly for Thermoplastic polymers such as Polyurethane, Polyolefin and PVC.

Foam Finishing

Foam finishing was developed as a more environmentally friendly version of the pad-dry-cure system, as the chemical applied requires less product in weight, but equates to a high surface area. Foam also ensures less wetting takes place, which requires less drying; furthermore waste is reduced in terms of residual liquor. This technique is useful in coating heavy fabrics such as carpets and can be used to effectively coat only one side. 

spray coating 

             similar like blade coating but instead of blade here we use  spray , because of costly coating chemical